Questions about Homo Sapiens' co-existence with other Hominin species
I've read that:
(1) Homo Sapiens came into existence 300,000 (maybe 400,000) years ago; (2) from the very beginning of the species, Homo Sapiens were anatomically identical to the Homo Sapiens of today, and
(3) Homo Sapiens co-existed with at least 4-5 other hominin species until 50,000 years ago or so.
Illustrations of those hominin species look like the drawing in this link:
https://www.britannica.com/science/human-evolution
Some questions come to mind. Were the first Homo Sapiens really anatomically identical to us today? Same size brain and skull shape? How certain is that view?
Why would there be no
evolution within Homo Sapiens over 300,000 years? Didn't racial and geographic characteristics at least develop over time (like skin color)?
How could Homo Sapiens look so different immediately from the other hominin species if they all a common ancestor species?